Contactor assembly for wire feeder

ABSTRACT

A portable wire feeder for providing welding wire and welding current to a welding operation includes an input electrically connected to a power source. An output is selectively electrically connected to the input to receive welding current delivered to the input from the power source and to provide the welding current and welding wire to the welding operation through a guide hose. A contactor includes a first electrical terminal, a second electrical terminal and a conductive bridge member for selectively electrically connecting the input to the output. The first electrical terminal is electrically connected to the input. The second electrical terminal is electrically connected to the output. The conductive bridge member is movable between the first position in which the bridge member electrically connects the first electrical terminal to the second electrical terminal and a second position wherein the bridge member is separated from at least one of the first and second electrical terminals to electrically isolate the terminals from one another. At least one of the first electrical terminals, the second electrical terminal and the bridge member is independently removable from the contactor for servicing or replacement. A motorized wire feeding system includes a motor and a feed roll driven by the motor to direct the welding wire from a wire supply to the output for provision of the welding wire to the welding operation through the guide hose.

BACKGROUND

1. Field of the Invention

Exemplary embodiments disclosed herein generally relate to electric arcengine welders, including those employing a welding gun for use in awelding operation and a wire feeder for supplying a consumable weldingwire electrode to the welding gun. More particularly, exemplaryembodiments disclosed herein relate to improved contactor assemblies forwelding wire feeders. The embodiments find particular application as (orin) portable electric arc engine welders, often used when the locationof the welding operation is not expected to remain constant, such as,for example, welding operations at job sites which change regularly orwelding operations covering large areas at a single job site. It is tobe appreciated, however, that the exemplary embodiments discussed hereinare also amenable to other like applications.

2. Discussion of the Art

Electric arc engine welders are generally well known. Typically, inelectric arc welders, a power source passes current between an electrodeand a work piece. Often, the electrode is a continuous welding wiredrawn from a supply of welding wire, such as a drum or reel, which ispassed through a contact tip or gun on its way to being melted anddeposited onto the work piece. The gun can be provided with aselectively operable switch for applying welding power from the powersource to the electrode (i.e., the wire) for establishing an arc betweenan exposed portion of the electrode and the work piece. Wire feeders areoften used to advance the welding wire, preferably in a consistent andcontrollable manner, to the welding gun for use in the weldingoperation. Welding wire feeders can be manufactured in several forms,each optimized for a specific application. Common classifications ofwire feeders include robotic wire feeders, portable wire feeders,tractor wire feeders and bench mount wire feeders.

Portable wire feeders are often used when the location of the weldingoperation or operations is likely to change or does not always remainconstant (e.g., shipyards). This might include, for example, weldingoperations at job sites that change day-to-day or welding operationsthat cover a large area at a single job site. Examples of portable wirefeeders are generally taught in the following U.S. Pat. Nos. 4,665,300Bellefleur; 6,213,375 Rybicki; 4,508,954 Kroll; 6,225,596 Chandler;5,410,126 Miller; 5,836,539 Grimm; and 6,705,563 Luo, all expresslyincorporated herein by reference.

Preferably, portable wire feeders are able to supply their respectivewelding operations with welding wire in a manner much like that of aconventional stationary wire feeder. This is often more difficult in theportable wire feeder because it is likely to be subjected to repeatedmovement and used in connection with a wide range of work environments,many of which can be severe. In contrast, conventional stationary wirefeeders are often used in controlled and unchanging environments, suchas a work shop or factory floor. In addition to functioning like astationary wire feeder, the portable wire feeder is preferably compactand lightweight enabling it to be more easily moved and used in confinedwork areas. Other desirable characteristics of portable wire feeders areruggedness and durability.

In one conventional welding arrangement, a portable wire feeder isconnected to a remotely positioned power source through a power sourcecable, also known as an electrode cable. The wire feeder is additionallyconnected to a welding gun by a guide hose. A motorized feeding systemin the wire feeder employs rollers to advance or pay welding electrodewire from a supply of wire (often a spool of wire) through the guidehose to the welding gun. For this purpose, the guide hose can include aninternal tube for transporting the wire from the feeder to the gun, inaddition to electrical wiring for providing power (such as controlcircuitry) to the gun. Optionally, the guide hose can further includepassageways for transporting shielding gas to the gun and/or forcirculating cooling fluid through or to the gun.

More particularly, portable wire feeders typically include a housing orenclosure with an input crimp or lug terminal for connecting the powersource cable to a bus bar, and an output connected to the guide hose towhich welding power from the power source is provided together with thewelding wire driven by the motorized wire feeding mechanism. Portablewire feeders, including the motorized wire feeding system and controlcircuitry thereof, can be powered by the arc current from the powersource. Portable feeders typically include a means for switching the arccurrent to the welding guide hose, such as a contactor. A trigger on thegun closes a switch to initiate the welding operation, which causes thecontactor to provide welding current to the guide hose and also startsthe motor for feeding wire to the guide hose. The welding arc currentflows through and is switched on and off by the contactor of theportable wire feeder.

Over time, contacts of the contactor, also referred to herein as anelectro-mechanical switch, deteriorate from the arcing and from heating.When this occurs, heretofore the whole contactor was replaced as acomplete unit. This had been considered desirable in the past because ofthe reduced inventory of parts required to service a wire feeder and thesimplification of the replacement process. However, there is a sizablesegment of the wire feeder market that has the skills necessary to do acontactor repair on a part-by-part basis and/or is willing to stockreplacement parts, including the several parts that comprise a contactorassembly. Often, these users are sensitive to the replacement costs ofthe contactor assembly and are continuously looking for cost savings.

Thus, for example, when the contacts of a contactor assembly are worn,and the remainder of the contactor assembly is in good condition, it maybe desirable to replace only the contacts. Typically, the coil and frameof the contactor assembly have longer useful lives than the contacts andmay not necessarily require replacement when the contacts initiallyfail. Thus, there is a need for improved portable wire feeders andcontactor assemblies therefor to facilitate replacement of selectedparts of the contactor assembly. This would enable a customer to replaceonly select components of the contactor assembly when it fails, ratherthan replacing the entire contractor assembly as a unitary component.Advantages to be gained include the lowering of replacement costsassociated with failing contactor assemblies, as well as reducingenvironmental waste.

SUMMARY

In accordance with one embodiment, a portable wire feeder is providedfor providing welding wire and welding current to a welding operation.More particularly, in accordance with this embodiment, the wire feederincludes an input electrically connected to a power source and an outputselectively electrically connected to the input to receive weldingcurrent delivered to the input from the power source and to provide thewelding current and welding wire to the welding operation through aguide hose. The wire feeder further includes a contactor for selectivelyelectrically connecting the input to the output. The contactor includesa first electrical terminal electrically connected to the input, asecond electrical terminal electrically connected to the output and aconductive bridge member movable between a first position in which thebridge member electrically connects the first electrical terminal to thesecond electrical terminal and a second position wherein the bridgemember is separated from at least one of the first and second electricalterminals to electrically isolate the terminals from one another. Atleast one of the first electrical terminal, the second electricalterminal and the bridge member is independently removable from thecontactor for servicing or replacement. A motorized wire feeding systemincludes a motor and a feed roll driven by the motor to direct thewelding wire from a wire supply to the output for provision of thewelding wire to the welding operation through the guide hose.

In accordance with another aspect, a welding wire feeder assembly isprovided. More particularly, in accordance with this embodiment, thewire feeder assembly includes a wire feeder housing having an inputelectrically connected to a power source to receive welding currenttherefrom and an output to which a guide hose is connected and extendsto a welding operation. A contactor assembly is disposed in the housingfor selectively electrically connecting the input to the output forproviding the welding current to the welding operation through the guidehose. The contactor includes a housing, a first stud removably securedto the housing and electrically connected to the input, and a secondstud removably secured to the housing and electrically connected to theinput. The contactor further includes a bridge member disposed withinthe housing and movable between a first position wherein the first andsecond studs are electrically connected through the bridge member and asecond position wherein the first and second studs are electricallyisolated from one another. An actuator is removably connected to thebridge member for moving the bridge member between the first and secondpositions. A motorized wire feeding system includes a motor and a feedroll driven by the motor to direct welding wire from a welding wiresupply to the output and through the guide hose to the weldingoperation.

In accordance with yet another embodiment, a contactor for an arcwelding wire feeder is provided. More particularly, in accordance withthis embodiment, the wire feeder includes a housing to which first andsecond electrical terminal studs are removably connected. The first studis electrically connected to an input power cable which delivers powerfrom a remotely positioned power source. The second stud is electricallyconnected to an output of the wire feeder wherein power provided to theoutput is electrically connected to a consumable electrode wire of thewire feeder. A conductive bridge member is removably disposed in thehousing and is movable between a first position in which the bridgemember electrically couples the first stud to the second stud and aposition in which the bridge member is separated from at least one ofthe first and second studs to electrically isolate the studs from oneanother. An actuator is removably connected to the bridge member to movethe bridge member between the first position and the second position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an electric arc welder having a wirefeeder connected to a power source for performing a welding operation ona workpiece.

FIG. 2 is a perspective view, partially exploded, illustrating anexemplary wire feeder contactor assembly in the wire feeding apparatusof FIG. 1.

FIG. 3 is an exploded view of the contactor assembly of FIG. 2,including an input stud, an output stud and a conductive bridge member.

FIG. 4 is a partial cross-sectional view of the contactor assembly ofFIG. 2 showing the bridge member in a position to electrically isolatethe studs from one another.

FIG. 5 is another partial cross-sectional view of the contactor assemblyof FIG. 2 showing the bridge member in a position electricallyconnecting the studs to one another.

FIG. 6 is a partial cross-sectional view of an alternate actuator foruse in a contactor assembly.

DETAILED DESCRIPTION

FIG. 1 schematically shows an electric arc welder or system for electricarc welding generally designated by reference numeral 10 according toone exemplary embodiment. The illustrated welder 10 includes a wirefeeder 12 connected to a remotely positioned power source 14 by an inputcable 16 (or electrode lead). Through the input cable 16, the powersource 14 delivers welding current to the wire feeder 12. As shown, thewire feeder 12 can be a portable wire feeder solely powered by an arcvoltage (or welding current) supplied by the power source 14. Thus,welding current is delivered to the wire feeder 12 by the input cable 16and power for the feeder's motorized feeding system 18, and the feeder'scontrol circuitry, is drawn from this welding current. Alternatively,the wire feeder can be configured as a tractor wire feeder or some othertype of wire feeder. Also, although not included in the illustratedembodiment, a control cable can optionally extend between the powersource 14 and the wire feeder 12, separately spaced from the electrodelead 16.

As is known and understood by those skilled in the art, the wire feedercontrol circuitry can be used to operate the motorized feeding system18; sense and display measurements related to the welding current, suchas display the arc voltage passing through to the gun 20; selectivelyconnect the welding wire 24 to the welding current supplied by the powersource 14, such as through contactor assembly 38; and/or enable thetrigger 20 a to be used for operating the contactor assembly 38. As isalso known and understood by those skilled in the art, the wire feeder12 is additionally connected to welding gun 20 by a guide hose 22. Themotorized feeding system 18 of the wire feeder 12 is used to selectivelyadvance or pay welding electrode wire 24 through the guide hose 22 tothe welding gun 20. As illustrated, the power source 14, which can be anAC or DC power source and can be fitted with whatever controls may beneeded, can be grounded (i.e., electrically connected) to work piece WPthrough a power source work lead or cable 26.

With the power source 14 grounded to a work piece WP, gun trigger 20 acan be actuated to selectively connect the welding current delivered tothe wire feeder 12 to the wire 24 passing through the guide hose 22 andcreate a welding arc between the gun 20 (and specifically an exposedportion of the electrode wire 24 a extending from the gun 20) and thework piece WP. Trigger 20 a can also be used to actuate the motorizedfeeding system 18 of the wire feeder 12 to deliver additional consumablewelding wire 24 to the gun 20.

More particularly, the wire feeder 12 provides additional weldingelectrode wire 24 when needed from a supply reel or spool 28 to theguide hose 22 via the motorized welding wire feeding system 18 and anoutput 32 coupled to the hose 22. As known and understood by thoseskilled the art, the power source 14 converts input power to providewelding current and voltage wave forms via the input cable 16 (electrodelead) for selective application of the welding signal to a weldingprocess through a circuit formed by the input cable 16, wire feederinput 34 with a first or input bus bar 36 and contactor type switchingdevice 38, also referred to herein as a contactor assembly, and throughsecond or output bus bar 40 providing electrical connection from thecontactor assembly 38 to the guide hose 22 at wire feeder output 32.Thus, the input 34 is electrically connected to the power source 14 andthe output 32 is selectively electrically connected to the input 34 toreceive welding current delivered to the input 34 from the power source14 and to provide the welding current to the welding operation (adjacentwire tip 24 a) through the guide hose 22. Specifically, it is thecontactor assembly 38 that selectively electrically connects the input34 to the output 32.

The work lead 26, which grounds the power source 14 to the work pieceWP, provides a power current return path. A workpiece sense cable orlead 42 is provided from the workpiece WP to a control board orcontroller 44 in the wire feeder 12, which communicates control signalswith the contactor assembly 38, the motorized wire feeding system 18 andthe output 32. The controller 44 is coupled to the contactor assembly38, output 32, and wire feeding system 18, and operates to control theoperating condition of the contactor assembly 38 and the wire feedingsystem 18 by providing a contactor control signal 46 and a wire feedcontrol signal 48 according to a trigger signal 50 from trigger 20 a ofgun 20 via output 32.

In operation, controller 44 generates contactor control signal 46 uponreceipt of trigger signal 50. More particularly, the controller 44provides the contactor control signal 46 in a first state toelectrically connect input stud 58 to output stud 60, both of thecontactor assembly 38, when the gun trigger 20 a is actuated, and in asecond state to electrically isolate input stud 58 from output stud 60when trigger 20 a is not actuated. Optionally, a thermal sensor 62 canbe provided on output bus bar 40, or adjacent the contactor assembly 38,for providing a temperature signal 64 to the controller 44. Thetemperature signal 64 can be used by the controller 44 in determiningwhether to provide contactor control signal 46 and/or to provideactuator control signal in the first or second state.

In operation during a welding procedure, an operator actuates trigger 20a on the gun 20 causing activation of on/off signal 46 from controller44 to selectively provide electrical connection between electricalterminals 58, 60 in a first or a closed operating condition or positionand to electrically separate or isolate electrical terminals 58, 60 fromone another in a second or open position. Thus, the operating conditionof the contractor assembly 38 determines whether electrical power isprovided to output 32 and hence controls application of welding currentto the welding workpiece WP through the gun 20 and guide hose 22. Themotorized feeding system 18 also receives electrical power from theoutput side of the contactor assembly 38 (e.g., from the second bus bar40), such that when the contactor assembly 38 is closed in a firstposition, the welder 10 provides welding wire 24 from supply reel 28 tothe guide hose 22 via output 32 at a controlled rate.

Reel 28 may be internal to or outside of (as illustrated) a wire feedinghousing enclosure 63, wherein welding wire 26 is drawn or paid out fromsupply reel 28 via feeding system 30. The feeding system 18 includes amotor (not shown) driving one or more feed reels 65 so as to direct wire24 from reel 28 to output 32 for provision of wire 24 to a weldingoperation through guide hose 22. The unillustrated motor of the feedingsystem 30 can be separately supplied or can be powered by power from thepower source 14 via contactor assembly 38 and output bus bar 40 asshown. The wire feeder 12 may also include apparatus (not shown) fordirecting shielding gas to the welding operation via the guide hose 22.

With additional reference to FIG. 2, the contactor assembly 38 includesan actuator, such as solenoid actuator 70 having coil leads 72, 74, thatselectively moves a conductive bridge member 76 for selective connectionor isolation of terminal studs 58, 60 according to contactor controlsignal 46 that selectively energizes or de-energizes coil 68 ofcontactor solenoid actuator 70. The conductive bridge member 76 can be,as illustrated, housed or enclosed within contactor housing 78, whichcan be formed of a relatively nonconductive material to isolate studs58, 60 from one another. As will be described in more detail below, thesolenoid actuator 70 includes magnetic sleeve coil 68 to which leads 72,74 are connected, core shaft member 100 received within coil 68, andsolenoid housing 106.

With additional reference to FIGS. 3-5, the studs 58, 60 of thecontactor assembly 38 each include a respective head portion 58 a, 60 a,a cylindrical base portion 58 b, 60 b and a threaded portion 58 c, 60 cextending from respective base portions 58 b, 60 b to respective ends 58d, 60 d. The head portions 58 a, 60 a can include respectivenoncylindrical or hexagonal portions 58 e, 60 e for limiting rotation ofrespective studs 58, 60 relative to contactor housing 78. Asillustrated, the contactor housing 78 can be formed of a plurality ofwalls, including rectangular main wall 78 a, and side walls 78 b, 78 c,78 d, 78 e depending from respective edges of main wall 78 a. End sidewalls 78 b, 78 c define apertures or cut-outs 78 f, 78 g. A raisedsection 78 b can extend from a surface of main wall 78 a opposite thatwhich faces bridge member 76 and has walls 78 b-78 e dependenttherefrom. The wall 78 a and raised section 78 h together define studapertures 78 i, 78 j that receive respective studs 58, 60 therein.Corresponding noncylindrical or hexagonal countersink portions 78 k, 78l of apertures 78 i, 78 j mate with respective hexagonal portions 58 e,60 e to limit rotation of the studs 58, 60 relative to the housing 78.

The studs 58, 60 are received in respective apertures 78 i, 78 j and areremovably connected or secured to the housing 78 by threaded fastenersor nuts 80, 82 which threadedly engage threaded portions 58 c, 60 c ofthe studs. Washers 84, 86 can be interposed between the nuts 80, 82 andthe raised portion 78 h of the housing 78. The input terminal stud 58 isfurther coupled to the input bus bar 36 by the threaded portion 58 cbeing received through first bus bar aperture 36 a and having threadedfastener or nut 88 threadedly received thereon. A washer 90 can bedisposed between the nut 88 and the bus bar 36. Similarly, the secondcontactor terminal stud 60 is coupled to the second or output bus bar 40by threaded portion 60 c being received through second bus bar aperture40 a and having nut 92 and washer 94 received thereon. Since theelectrode lead 16 electrically connects the power source 14 to the firstbus bar 36, switched power is provided to the wire feeding system 18 andoutput 32 when the contactor assembly 38 is in the closed condition(shown in FIG. 5).

As will be described in more detail below, the conductive bridge member76 of the contactor assembly 38 is removably connected to the solenoid'score shaft member 100 which is movable by the solenoid's coil 68. Moreparticularly, the bridge member 76 is movable by the core shaft member100 according to the contactor control signal 46 applied by thecontroller 44 (FIG. 1) to solenoid control leads 72, 74 between a firstposition (FIG. 5) in which bridge member 76 electrically couples thestuds 56 and 60 to one another and a second position (FIG. 4) in whichbridge member 76 is separated from the studs 56, 60 to therebyelectrically isolate the contactor terminals and inhibit current flow tothe welding gun 20 and wire feeding system 18.

The bridge member 76 can be formed of any suitable conductive material,and may include a conductive contacts 76 a, 76 b, as illustrated, facingor adjacent the stud heads 56 a, 60 a. In the illustrated embodiment,bridge body 76 c defines an aperture 76 d for mounting the bridge meansto the shaft member 100. More particularly, in the illustratedembodiment, sleeve mounting member 102 has a shaft portion 102 areceived through bridge aperture 76 d and a head portion 102 b whichrests against the bridge body 76 d. The shaft portion 102 c has adiameter substantially matching a diameter of the bridge aperture 76 d.Sleeve mounting member 102 further includes an axial throughhole 102 c.The sleeve mounting member 102 can be formed of a generallynonconductive material and referred to as an insulator for electricallyisolating the bridge member 76.

Distal portion 100 a of core shaft member 100 is received through thethroughhole 102 c and thereby through bridge aperture 76 d. Threaded end100 b receives a threaded fastener or nut 104 thereon to fixedly securethe shaft member 100 to the bridge member 76. In particular, nut 104 canbe received within counter sink 102 d of sleeve mounting member 102. Theshaft member 100 is generally formed of a material such that it can bemoved by the coil 68 when electricity is supplied thereto by leads 72,74. As is known to those skilled in the art, the direction of currentsupplied by leads 72, 74 determines the direction of movement of theshaft member 100 within the coil 68.

The actuator 70 includes a housing 106 having base wall 106 a and sidewalls 106 b, 106 c extending from opposed edges of base wall 106 a. Asillustrated, the housing 106 can include integral sleeve member 106 dfixedly attached to base wall 106 a and extending therefrom between sidewalls 106 b, 106 c. The housing 106 can be connected to the contactorhousing 78. More particularly, common wall assembly 108, includingcommon wall member 108 a and sleeve 108 b, can be fixedly secured to thesolenoid housing 106 and to a contactor housing 78. In the illustratedembodiment, the side walls 106 b, 106 c can be partially received inelongated slots 108 c defined in common wall member 108 a and rivetconnected thereto (i.e., headless end of walls 106 b, 106 c hammered soas to form an elongated head that prevents removal of common wall member108 from solenoid housing 106) resulting in rivet ends 106 f, 106 g.With reference to FIG. 2, contactor housing 78 can be connected tocommon wall member 108 a by any removable fastening means, such as byone or more conventional elongated fasteners or bolts 110 threadedlyengaged with wall member 108 a

When assembled, core shaft member 100 has its base 100 c received insleeve member 106 d such that shaft member base flange 100 d can restagainst end 106 e of sleeve member 106 d (when contactor is in its firstposition of FIG. 5). Cap 111 can be snap-fit onto the sleeve member 106d extending from base wall 106 a in a direction opposite side walls 106b, 106 c. Coil 68 is received annularly about the sleeve member 106 d(i.e., sleeve member 106 d is received in coil aperture 68 a). Whendisposed in sleeve member 106 d, axial movement of shaft member 100(such as caused by current being provided to coil 68 via leads 72, 74)is limited in one direction by flange 100 d engaging sleeve end 106 eand in the opposite direction by flange 100 d engaging end 108 d ofsleeve member 108 b.

More particularly, shaft portion 100 e is received through sleeveaperture 108 e. Telescoping sleeve members 112, 114 which can be formedof a relatively non-conductive material, are disposed between bridgemember 76 and wall member 108 a, and further disposed about the shaftmember 100. Washer member 100 f can be disposed on shaft 100 a toprovide a seat to spring 116. As shown, washer member 100 f can bereceived in countersink 108 f of sleeve member 108 b. Spring 116 can bedisposed around shaft member 100 and between bridge member 76 and shaftflange 100 f, and further disposed within the sleeve members 112, 114such that spring 116 urges the sleeve members 112, 114 axially apartfrom one another.

One or more springs, optionally including spring 116, can be providedfor urging the conductor bridge member 76 toward the second (open)position (position shown in FIG. 4). In the illustrated embodiment, mainspring 120 is installed between bridge member 76 and main housing wall78 a for urging the bridge member 76 toward the second position. Mainwall 78 a includes spring retention structure 78 m for positioning thespring 120 and connecting the spring 120 to the housing 78. An oppositeend of the spring 120 is received over nut 104 in a countersink 102 d.Insulator sleeve 102 electrically isolates bridge member 76 from thespring 120.

In operation, spring 120 urges or biases conductive bridge member 76toward the second or open position of FIG. 4, such that upon loss ofcontrol signal 46, the contactor assembly 38 goes to a fail-safe openposition. As shown in FIG. 5, application of control signal 46 of afirst state to the two solenoid leads 72, 74 causes the solenoid shaftmember 100 to move the bridge member 76 in a first direction 122 towardthe first position for electrically connecting the studs 56, 60.Applying a second signal state 46 moves the bridge member 76 in a secondopposite direction to the second position of FIG. 4 to effectivelyseparate the bridge member 76 from the studs 56, 60 and therebyelectrically isolate the studs from one another. The first state signal46 can simply be the provision of power to the leads 72, 74 in a firstdirection, appropriate for moving the core shaft member 100 in thedirection 122 and the second state signal 46 can be the provision ofpower to the leads 72, 74 in a second opposite direction.

Unlike prior art contactor assemblies, the illustrated contactorassembly 38 is constructed such that its components can be individuallyremoved, serviced and/or replaced. More particularly, most components ofthe contactor assembly 38 are removably attached or connected to othercomponents of the contactor assembly. Accordingly, when one componentfails or is otherwise ready for servicing or replacement, that componentcan be removed, serviced and/or replaced, and then reinstalled in thecontactor assembly. In the illustrated embodiment, each of the studs andthe bridge member 76 is independently removable from the contactorassembly 38 for servicing and/or replacement. For example, each of thecontacts or studs 58, 60 can be serviced or replaced once worn,particularly when the remainder of the contactor assembly 38 is in goodcondition.

To remove the studs 58, 60, the contactor assembly 38 is disconnectedfrom the bus bars 38, 40 by removing nuts 88, 92 and their correspondingwashers 90, 94. Next, the contactor housing 78 can be disconnected fromthe solenoid housing 106. In the illustrated embodiment, fasteners 110are removed so that housing 78 can be detached from common wall assembly108. With the housing 78 removed, the studs 58, 60 (one or both) can beremoved from the housing 78 by unthreading respective nuts 80, 82 andpulling the studs from the housing.

Other components of the contactor assembly 38 can also be individuallyremoved, serviced and/or replaced, and subsequently reinstalled. Forexample, the spring 120, which is removably secured within the housing78, could be replaced when the contactor housing 78 is detached from thesolenoid housing 106. Though the spring 120 is held to the housing wall78 a by retention structure 78 m, the spring 120 (or the structure 78 m)can be resilient enough to permit detachment of the spring from thehousing 78. The bridge member 76 can be removed by unthreading nut 104from core shaft member 100. Likewise, insulator 102 and sleeves 112,114could be replaced.

The actuator 70 is also independently removable from the contactorassembly 38 and therefore could be removed and replaced separately fromthe components housed in contactor housing 78. In the illustratedembodiment, the coil 68, housing 106, core shaft 100 and common wallassembly 108 can be replaced as an integral unit. However, in alternateconstructions, coil 68, housing 106, core shaft 100 and common wallstructure 108 can be individually replaceable. For example, in onealternate construction shown in FIG. 6, the rivet connection betweenhousing 106 and common wall assembly 108 is replaced by a more removabletype connection. In the illustrated alternate embodiment, common wallassembly 108′ is removably secured to actuator housing 106′ viafasteners 130. The fasteners 130 can be removed so that common wallassembly 108′, including wall 108 a and sleeve 108 b, can be removed(i.e., disconnected) from the housing 106′. This enables individualremoval access to coil 68′ and core shaft 100′, as well as to the wallassembly 108′ and the housing 106′. Individual removal access enablesthese components to be individually removed, serviced and/or replaced.To facilitate replacement of specific component parts of the contactorassembly 38, one or more components (such as contactor studs 58, 60;spring 120, bridge member 76, insulator 102, etc.) can be packagedindividually or together in any combination as a kit.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Variouspresently unforeseen or unanticipated alternatives, modifications,variations, or improvements therein may be subsequently made by thoseskilled in the art which are also intended to be encompassed by thefollowing claims.

1. A portable wire feeder for providing welding wire and welding currentto a welding operation, the wire feeder comprising: an inputelectrically connectable to a power source; an output selectivelyelectrically connectable to said input to receive welding currentdelivered to said input from said power source and to provide saidwelding current and welding wire to the welding operation through aguide hose; a contactor for selectively electrically connecting saidinput to said output, said contactor including a contactor housing, afirst electrical terminal removably connected to said contactor housingand electrically connected to said input, a second electrical terminalremovably connected to said contactor housing and electrically connectedto said output, and a conductive bridge member movable between a firstposition in which said bridge member electrically connects said firstelectrical terminal to said second electrical terminal and a secondposition wherein said bridge member is separated from at least one ofsaid first and second electrical terminals to electrically isolate saidterminals from one another, and said bridge member independentlyremovable from said contactor; and a motorized wire feeding systemincluding a motor and a feed roll driven by said motor to direct saidwelding wire from a wire supply to said output for provision of saidwelding wire to the welding operation through said guide hose.
 2. Theportable wire feeder of claim 1 wherein said contactor further includesan actuator operable according to a contractor control signal toselectively move said bridge member between said first and secondpositions, said control signal having a first state in which saidactuator moves said bridge member to said first position and a secondstate in which said actuator moves said bridge member to said secondposition.
 3. The portable wire feeder of claim 2 wherein each of saidfirst electrical terminal, said second electrical terminal, said bridgemember and said actuator is independently removable from said contactorfor servicing or replacement.
 4. The portable wire feeder of claim 2wherein said actuator is a solenoid actuator.
 5. The portable wirefeeder of claim 4 wherein said solenoid actuator includes a magneticsleeve coil and a core shaft member disposed within said magnetic sleevecoil, said core shaft member having said bridge member removablyconnected thereto so that said coil moves said core shaft member andsaid bridge member toward said first position when current is providedto said coil in a first direction and moves said core shaft member andsaid bridge member toward said second position when current is providedto said coil in a second direction.
 6. The portable wire feeder of claim6 wherein said coil and said core shaft are independently removable fromsaid contactor.
 7. The portable wire feeder of claim 5 wherein saidsolenoid actuator includes a solenoid housing in which said coil isdisposed, said solenoid housing, said coil and said core shaft eachindependently removable from said contactor.
 8. The portable wire feederof claim 1 wherein said first electrical terminal is a stud electricallyconnected to an input bus bar that is electrically connected to an inputpower cable for delivering power from said power source.
 9. The portablewire feeder of claim 1 wherein said second electrical terminal is a studelectrically connected to said output through an output bus bar.
 10. Theportable wire feeder of claim 1 further including a controller forcommunicating control signals with at least one of said contactor, saidmotorized wire feeding system and said output, said controller providinga contactor control signal to said contactor to control an operatingcondition of said contactor in accordance with a trigger signal receivedfrom a gun of said guide hose through said output.
 11. The portable wirefeeder of claim 10 wherein said controller provides said contactorcontrol signal in a first state when a trigger of said gun is actuatedand said controller provides said contactor control signal in a secondstate when said trigger is not actuated.
 12. The portable wire feeder ofclaim 10 further including a thermal sensor adjacent said contactor forproviding a temperature signal to said controller, said contractorcontrol signal provided in accordance with said trigger signal and saidtemperature signal.
 13. The portable wire feeder of claim 12 whereinsaid controller provides said contactor control signal in a first statewhen a trigger of said gun is actuated and said temperature signalindicates said contactor is below a predetermined threshold temperature,and wherein said controller provides said contactor control signal in asecond state when said trigger is not actuated or when said contactor isabove said threshold temperature.
 14. The portable wire feeder of claim1 wherein first electrical terminal is a first stud electricallyconnected to an input bus bar that is electrically connected to an inputpower cable for delivering power from said power source, and whereinsaid second electrical terminal is a second stud electrically connectedto said output through an output bus bar.
 15. The portable wire feederof claim 14 wherein said first and second studs each include threadedportions received through respective apertures defined in each of saidinput and output bus bars, said threaded portions threadedly engagedwith threaded fasteners to removably secure said first and second studsto said input and output bus bars.
 16. The portable wire feeder of claim1 wherein said contactor includes a housing, said first and secondelectrical terminals are studs having threaded portions received throughapertures defined in said housing, said threaded portions threadedengaged with threaded fasteners to removably secure said first andsecond studs to said housing.
 17. The portable wire feeder of claim ofclaim 16 wherein said bridge member is disposed within said housing andremovably connected to an actuator for moving said bridge member betweensaid first position and said second position.
 18. The portable wirefeeder of claim 17 wherein said contactor further includes a springdisposed within said housing between a main wall of said housing andsaid bridge member to urge said bridge member toward said secondposition, said spring removably secured within said housing tofacilitate replacement thereof.
 19. The portable wire feeder of claim 16wherein an insulator is disposed between said bridge member and saidactuator to electrically isolate said bridge member and said actuatorfrom one another, said insulator removable from said contactor.
 20. Theportable wire feeder of claim 16 wherein the housing is a portablefeeder housing.
 21. A contactor for a welding wire feeder, comprising: acontactor housing to which first and second electric terminal studs areconnected, said first stud electrically connectable to an input powercable which delivers power from a remotely positioned power source andsaid second stud electrically connectable to an output of a wire feederwherein power provided to the output is electrically connected to aconsumable electrode wire of the wire feeder; a conductive bridge memberdisposed in said contactor housing and movable between a first positionin which said bridge member electrically couples said first electricalstud to said second stud and a second position in which said bridgemember is separated from at least one of said first and secondelectrical studs to electrically isolate said studs from one another; anactuator housing connected to said contactor housing, and an actuator atleast partially disposed in said actuator housing, said actuatorconnected to said bridge member to move said bridge member between saidfirst position and said second position.
 22. The contactor of claim 21further including a spring removably disposed in said housing for urgingsaid bridge member toward said second position.
 23. The contactor ofclaim 21 wherein said actuator includes a magnetic sleeve coil and acore shaft member disposed with said magnetic sleeve coil, said coreshaft member having said bridge member removably connected thereto sothat said coil moves said core shaft member and said bridge membertoward said first position when current is provided to said coil in afirst direction and moves said core shaft member and said bridge membertoward said second position when current is provided to said coil in asecond direction.
 24. The contactor of claim 23 wherein said actuatorincludes a solenoid housing in which said coil is disposed, saidsolenoid housing, said coil and said core shaft each removably connectedto one another.